1. Field
Provided is a liquid crystal display and an optical compensation film for the liquid crystal display.
2. Description of the Related Art
A twisted nematic (“TN”) mode liquid crystal display (“LCD”) is widely used in various devices, such as a monitor and a television set, for example. In a TN mode LCD, a nematic liquid crystal material is typically homogeneously aligned with a slight pretilt angle, and the azimuthal angle of the liquid crystal molecules is gradually twisted from a substrate to the other substrate by about a right angle. The director of the liquid crystal molecules is varied by applying a vertical electric field to the liquid crystal layer of the TN LCD to adjust optical transmittance, thereby displaying images.
In the TN mode LCD, unlike vertical alignment (“VA”) and in-plane switching (“IPS”) mode LCD, the average direction of the liquid crystal director may point downward relative to the front direction such that image quality may be impaired when viewing the TN mode LCD upwardly and downwardly. However, the TN mode LCD has a better image quality in leftward and rightward directions compared to the VA and IPS mode LCD.
A wide-viewing (“WV”) film may be used to improve the upward and downward viewing characteristics of the TN mode LCD. The WV film is manufactured by aligning a liquid crystal material with a discotic nematic phase such that the direction of the liquid crystal director gradually changes along the thickness direction.
However, discotic liquid crystal material, which is typically used in the WV film, may not be cost-effective when used for a large-sized WV film since the discotic liquid crystal materials are substantially expensive.
In addition, light leakage may occur in a black state of a normally white TN mode LCD, thereby decreasing the contrast ratio.